Ultimate Core

The HDF core is first calibrated by a drum sander using 120 and 180 grit sandpaper. The board then enters the roll coating line where one coat of clear primer and one coat of clear sealer is applied and cured through 2 UV light tunnels for a total of 6 mils of applied finish per side. The board is then final sanded to a grit of 360. This process is repeated for both sides of the board.

The core is manufactured from specialty Super Refined Fiber. Double Refined fiber is processed differently using a high energy refiner that acts as a steam pressurized “digester”, allowing the raw material to become softened and to actually change physically and chemically. APPI’s “Ultimate Core” is a low emissions HDF that meets C.A.R.B. II emission standards and manufactured with a No Added Formaldehyde resin. (NAF)

When it comes to value, what really counts is not how much the HDF costs, but how much it costs to use it. Not all High Density – MDF panels are alike, and may differ by wood species, fiber size, binders, density, and consistency. All of these factors have a significant impact on key elements of your processing costs including:

• Cutting tool life
• Machine center throughout the speed and amp load
• Machined profile quality as it relates to the need for sanding, filling, and other steps prior to finishing
• Defect rates
• Labor

The superior uniformity and overall panel integrity of our “Ultimate Core” HDF outperforms other MDF products by allowing our customers to move it through their process faster while achieving higher quality results and lower production costs.

Ultimate Core HDF products are prized by woodworkers for their exceptionally flat, smooth, and unblemished surfaces. Our products are made from high-quality inland species of western softwoods known for their low abrasive content and light color and consistent results with a variety of finish materials.

The ultimate core provides a 52lb density and a 185lb internal bond (based on ¾” thickness) resulting in the highest-rated HDF available on the current market for strength and consistency. The linear expansion limit is also 25% less than the industry-accepted ANSI A208.2-2016 value of 0.33%.

Pre-finished surfaces reduce labor time, increasing productivity and efficiency in fabrication, and prevents bottlenecks common at the spray booth.


  • Calibrated before and after finishing resulting in a consistent thickness across the entire board (beneficial for CNC processing)
  • Sealed on both sides producing excellent vacuum positioning, greatly reducing any movement during machining in all 3 AXIS. (X, Y, Z)
  • Excellent for 1-piece shaker or raised panel doors reducing sanding and finish time. (it is recommended sealer be applied to machined areas immediately after being removed from the CNC table to further restrict warping)
  • The amount/thickness of coating material required for adequate coverage is greatly reduced.
  • Perfect for water or solvent-based paints/coatings
  • SFI Certified Sourcing
  • ECC Standard 4-11 Environmentally responsible use of wood fiber


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